The in vitro metabolism of selected carcinogenic nitrogen containing heterocyclic polynuclear aromatic hydrocarbons including benzo(c)acridine and dibenzo(a,h) acridine will be investigated. Conditions with and without high levels of 3-methylcholanthrene-induced mixed function oxidase activity will be employed. In additon to metabolism by mixed function oxydases, the extent of bioconversion of these compounds by other enzymatic processes will be determined. The ultimate goal of the project is to determine the similarities and differences in the metabolic fate and biological actions of the polynuclear aromatic hydrocarbons and their nitrogen containing analogs.